The present invention relates to a fire suppressing apparatus and more specifically to a gas generator to produce a large quantity of inert gas of low oxygen concentration within a short period of time. The present invention also relates to vehicles equipped with such gas generator to suppress fire.
In general, water or inert gases such as carbon dioxide, nitrogen, Halon1301, and Inergen have been used as means for fire suppressing. Among these, water is known to be the most effective fire suppressant and is also acknowledged to have the highest fire extinguishing effect. Here, fire-suppressing effect means both cooling and suffocating capabilities at time of fire suppressing.
However, in case water is used as a fire suppressant, it is required to cover all fired surfaces for complete extinction and therefore results in prolonging of fire suppressing time, thereby involves complicated problem of transporting a large quantity of water to the fire area. This inevitably makes the work less economical.
On the other hand, even though fire suppressants such as carbon dioxide, nitrogen, Halon1301, foam, etc., can temporarily suppress fire, their manufacturing cost are comparatively high and are usually intended for initial suppressing of fires of rather small size. Consequently, most of the fire suppressants existing today except water are thought to be not successful in suppressing fires of a great magnitude.
The sprinkler system has also been used effectively as a fire extinguishing equipment for fires occurring in large structures. The sprinkler system consists of a hydraulic pump to pressure the working-fluid, a valve to activate the fire alarm system with due connection to the hydraulic pump, an ejection nozzle and sprinkler head to distribute water to interior compartment. The sprinkler here includes a soluble link which melts at a preset indoor temperature at the time of fire and a deflector to distribute pressurized fluid with a certain degrees of angle.
However, this type of fire-extinguishing equipment has disadvantages in that it is required to spread the pressurized fluid through hydraulic pumps and therefore consumes a large amount of water. Sometimes it has malfunction due to increased interior temperature and accordingly requires a considerable time to suppress the fire. In reality, various types of scheme to initially suppress the fire are proposed as well as to improve its capability.
For instance, U.S. Pat. No. 4,113,019 discloses an inert gas generator for fire extinguishing using a turbo jet engine. According to the patent, the generator is equipped with diffuser at afterburner exit and a pressure reduction chamber sits between the afterburner and diffuser. The pressure reduction chamber is equipped with a manifold to which compressed inert gases such as nitrogen are introduced from outside. The compressed inert gases induced in the pressure reduction chamber will be decompressed and sent to the fire area. A diffuser will introduce the Freon gas into the exhausting inert gas thus increasing the fire suppressing efficiency.
However, U.S. Pat. No. 4,113,019 does not actually describe an equipment that produces inert gas as fire suppressant itself but acts as a simple introductory path to guide already manufactured inert gas of high kinetic energy by other mechanism to eject outward to the fire area. As this mechanism utilizes nitrogen and Freon gas as inert gas, the resulting cost for fire extinguishing tends to increase and brings harmful effect to the environment.
International Patent Laid-Open No. WO-9318823 discloses case where a turbo jet gas turbine is applied in fire suppressing. The turbo jet gas turbine is employed to spray water to the fire area utilizing high momentum existing at the gas turbine exit as well as to lower the exhaust gas temperature. The turbo jet gas turbine has often been used for special purposes such as suppressing the oil well fire by temporarily cutting off the oxygen entrainment from the atmosphere into the fire area but is known to have disadvantage of consuming too much water.
An USSR Pat. No. SU-1724275 discloses equipment for fire suppressing in a special region like an airport by spreading powdered inert gases with high temperature compressed air generated by a compressor. However, this system needs to have a separate power source and therefore, is difficult to operate for a longer time not to mention the difficulties in producing a large amount of inert gas.
Also, China Pat. No. CN-1110184 discloses a generator for driving a gas turbine. This generator intends to suppress the fire by transmitting a large quantity of water to the fire area by a water pump, but in general, is similar to conventional fire car and accordingly contains same drawbacks as others described above.
German Pat. No. DE-19625559 discloses a fire suppressing system using a small sized gas turbine in limited spaces like a ship""s machine room or a small sized building. The equipment suppresses the fire by supplying nitrogen and water resulting from reaction of nitrogen and oxygen from the air. It has advantages that reaction material doesn""t include other toxic components such as carbon dioxide or others and is friendly to the environment. Nevertheless, the system is known to have complicated manufacturing procedures and hard to produce large quantity of nitrogen and water thereby difficult confront fires in large scale.
The present invention is to solve the problems brought up thus far and a major purpose is to provide an inert gas generator and its associated system to suppress fires using a turbo generator gas turbine
In addition, it is intended to produce a large amount of inert gases of low oxygen content and temperature through combustion processes in the turbo jet gas turbine and afterburner using an atmospheric air as its primary source.
Aforementioned objectives can be achieved by an inert gas generator for fire suppressing comprising: a gas turbine, which comprises a starter motor to drive initially the gas turbine, a compressor being connected to said starter motor, a combustor being connected to a fuel pump to burn air compressed in the compressor, and a turbine body installed at an exit of the combustor to generate power through expansion process; an afterburner being connected and installed at an exit of the turbine body, being connected to the compressor by a bleed off line to be provided with a portion of air extracted from the compressor for fuel atomizing and to re-bum gas burned in the combustor, and supplied through the turbine body, and being provided with a flame stabilizer to stabilize flame produced by re-burning of the gas burned in the combustor; a cooling chamber enclosing the afterburner to take combustion heat in the afterburner and to inject water through spray nozzles into gas re-burned in the afterburner to decrease temperature of the re-burned gas; an evaporator being installed at an exit of the cooling chamber for further cooling the re-burned gas which is already been cooled by the cooling chamber and the spray nozzles; an exhaust nozzle for guiding exhaust gas which has been cooled in the evaporator to a fire area; and a controller for controlling the starter motor, the fuel pump, the combustor and the afterburner.
According to the present invention, the inert gas generator comprises a starting motor system for supplying the power sufficient for the gas generator to reach self sustaining speed as it can not produce enough power to drive compressor and fuel pump system during low range of speeds. This starter motor will be separated once the system reaches the self-sustaining speed.